This invention relates to an exercise bicycle, more particularly to an exercise bicycle which has pedals disposed in front of the seat thereof.
In my U.S. Pat. applications, Ser. Nos. 07/192,166, 07/298,692 and 07/343,593, (the former two having been patented under U.S. Pat. Nos. 4,824,102 and 4,852,872, the latter one having been granted but not yet patented), I disclosed wind-drag type exercise bicycles for exercising arms and legs, each of which has foot operated pedals positioned below the seat thereof. These exercise bicycles can offer an intense amount of exercise to the entire body of the user. Nowadays, however, it is sometimes necessary for those doing office work to effectively exercise their legs while keeping the upper parts of their bodies as relaxed as possible. Accordingly, the improvement of this invention is directed to the conventional exerciser bicycle shown in FIG. 1, which is used solely to exercise a user's legs via pedals positioned in front of the seat thereof. As illustrated, the conventional exercise bicycle includes a frame assembly 1, a drive assembly 2, a wheel assembly 3, a chain 4 and two side shields 5. The frame assembly 1 consists of a front frame portion 11 and a rear frame portion 12. The rear end of the front frame portion 11 is inserted into the front end of the rear frame portion 12 and is locked on the same by a locking bolt 13. When the bicycle is viewed from the top, the front frame portion 11 of the frame assembly 1 has a generally U-shaped front end portion which is constructed of two parallel arms 111. Each of the arms 111 has an open-ended slot 112 formed in the upper surface thereof. The front frame portion 11 includes a horizontal body, an inverted T-shaped support 113 extending downward from the horizontal body, and a support frame 114 extending upward from said horizontal body. A bearing means 115 is disposed on the support frame 114. An L-shaped plate 116 is secured to the support frame 114. The rear frame portion 12 includes an inclined rear end portion extending from the horizontal body thereof, and two handlebars 14 disposed on two sides of the seat 15 of the bicycle. The drive assembly 2 includes a driving shaft (not shown) journalled on the bearing means 115, a driving sprocket 20 sleeved rigidly on the driving shaft, two crank arms 21 respectively secured to two ends of said driving shaft, and two pedals 22 respectively secured to the crank arms 21. The wheel assembly 3 includes a wheel 32 made of cast iron, and a driven sprocket 33 connected coaxially to the wheel 32. The wheel 32 has an annular groove (not shown) formed in the circumferential surface thereof. A brake belt 33 is connected securely to the L-shaped plate 116 and is engaged with the groove of the wheel 32. An adjusting means 51 is disposed on one of the side shields 5 so as to enable the user to adjust the gripping force of the brake belt 33 on the wheel 32. The axle 35 of the wheel 32 is journalled within the slots 112 of the arms 111. The chain 4 is trained on the driving sprocket 20 and the driven sprocket 30. The utilization of the brake belt 33 on the exercise bicycle has the following disadvantages:
(1) Because the brake belt 33 tends to push both the wheel 32 and the driven sprocket 30 toward the driving sprocket 20, after the bicycle has been used for a long period, the chain 4 loosens on the driving sprocket 20 and the driven sprocket 30. As a result, the longer the period for which the bicycle is used, the more the noise resulting from the engagement between the chain 4 and the sprockets 20, 30, adding tension-creating noise to what should be a tension-releasing exercise.
(2) Because the gripping force of the brake belt 33 on the wheel 32 is adjustable, the engagement between the brake belt 33 and the wheel 32 also creates much noise after long-term use.
(3) The brake belt 33 must be replaced after it wears to a certain extent.